Field of the Invention
The present invention relates to an X-ray generation apparatus that is applicable to non-destructive X-ray imaging in the fields of medical equipment and industrial equipment and so forth, and a radiography system having the X-ray generation apparatus.
Description of the Related Art
As of recent, X-ray inspection apparatuses having micro-focus X-ray generation tubes have come to be used in inspection of electronic devices. The micro-focus X-ray generation tubes applied to such X-ray inspection apparatuses are known to be transmission X-ray generation tubes having transmission targets. Transmission X-ray generation tubes are advantageous in comparison with reflection targets, with regard to the point that a broad radiation angle, a short source-object distance (SOD), and a great enlargement factor, can be ensured.
Japanese Patent Laid-Open No. 2012-104272 discloses a transmission micro-focus X-ray generation tube where electroconductive bellows are disposed behind the target, thereby suppressing charging of the bellows due to backward scattered electrons and stabilizing the electron trajectory. Japanese Patent Laid-Open No. 2012-104272 further discloses that the transmission micro-focus X-ray generation tube described therein improves positional accuracy of the focal point and reduces out-of-focus states, due to suppressing charging.
Japanese Patent Laid-Open No. 2002-298772 discloses a transmission micro-focus X-ray generation tube where an electron emitting source having a focusing lens electrode at the tip thereof is in close proximity of the target.
Both Japanese Patent Laid-Open No. 2012-104272 and Japanese Patent Laid-Open No. 2002-298772 disclose a transmission micro-focus X-ray generation tube having an electron emitting source that protrudes toward the target, and a tubular anode member extending at the cathode side so as to overlap the electron emitting source in the axial direction of the tube.